(135a) Surface Wettability and Roughness Play a Key Role in Bacterial Adsorption Kinetics

Waterborne bacterial proliferation on solid substrate surfaces poses a serious challenge in fields ranging from transportation to manufacturing. In the context of food safety, the cross-contamination of food products via contact with food preparation surfaces is a major concern. It has been estimated that in the United Sates, foodborne pathogens are annually responsible for 48 million illnesses and 3,000 deaths. Approximately 64% of these infections are bacterial in origin. Surface patterning techniques such as reactive ion etching, wet chemical etching, and mechanical abrasion were used to create micro- and nano-scale roughness features on quartz and glass substrates. The topographies of modified quartz and glass surfaces were characterized using atomic force microscopy to evaluate surface roughness and related physical parameters. Static water contact angle analysis was used to evaluate surface wettability. Agar plating and scanning electron microscopy were used to quantify bacterial adsorption and evaluate colony formation on the substrates. The roles of surface roughness and wettability in bacterial adsorption kinetics were explored. A 75-fold variation in adsorbed bacterial density was observed. Models were prepared to correlate surface roughness and wettability to the adsorption rates of Salmonella enterica Typhimurium LT12, Escherichia coli O157:H7and Listeria innocua Gram-negative and Gram-positive foodborne pathogenic bacteria. Kinetic models were developed, describing activation energies. This fundamental study of the importance of key physical surface parameters in bacterial adsorption may provide the basis for future development of surface preparations resistant to bacterial fouling. Such preparations could have significant impacts when it comes to food safety and human health.